[openstack-dev] [Congress] Mid-cycle sprint

Zhou, Zhenzan zhenzan.zhou at intel.com
Fri Jun 19 06:07:39 UTC 2015

Hi, Tim

I have looked at the request_fresh_action. One big question is that it requires external services to queue up changes and then call this Congress API at some point. I’m not sure they would buy in this design as many projects have notification mechanism ready now and Ceilometer heavily depends on these notifications.  So basically I prefer to use oslo.messaging. But this API is still useful for other external services that don’t use oslo.messaging notification to publish changes and are willing to integrate with Congress this way.
Anyway, I can upload my draft bp for review at first.

Zhou Zhenzan

From: Tim Hinrichs [mailto:tim at styra.com]
Sent: Wednesday, June 17, 2015 21:57
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [Congress] Mid-cycle sprint

Hi Zhenzan,

Yes the oslo.messaging integration task is relevant--oslo.messaging is one way of achieving cross-process, cross-host messaging.  So I'll count you as interested for the mid-cycle sprint.

Have you looked at the API call that forces a datasource driver to pull immediately?   See congress/api/datasource_model.py:DatasourceModel.request_refresh_action.  We had envisioned using that to implement a kind of notification from external services as follows.  The external service queues up a list of changes and when the queue is long enough runs the API call to force the datasource driver  hooked up to that service to pull those changes and then publish them on the bus.  So it's not exactly streaming updates from the external service (which is good so that Congress can easily rate-limit updates), but it has almost the same effect.


On Tue, Jun 16, 2015 at 6:02 PM Zhou, Zhenzan <zhenzan.zhou at intel.com<mailto:zhenzan.zhou at intel.com>> wrote:
Hi, Tim

Is this the oslo.messaging integration task? I’m interested in participating. Actually I am working on a bp to receive notifications from external services in datasource driver at first. I’m ok to change if the direction is to integrate oslo.messaging thoroughly (even replacing DSE).

Zhou Zhenzan

From: Tim Hinrichs [mailto:tim at styra.com<mailto:tim at styra.com>]
Sent: Wednesday, June 17, 2015 05:14
To: OpenStack Development Mailing List (not for usage questions)
Subject: [openstack-dev] [Congress] Mid-cycle sprint

Hi all,

In the last couple of IRCs we've been talking about running a mid-cycle sprint focused on enabling our message bus to span multiple processes and multiple hosts.  The message bus is what allows the Congress policy engine to communicate with the Congress wrappers around external services like Nova, Neutron.  This cross-process, cross-host message bus is the platform we'll use to build version 2.0 of our distributed architecture.

If you're interested in participating, drop me a note.  Once we know who's interested we'll work out date/time/location details.


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